The invention relates generally to the field of ceramic matrix laminates. More specifically, embodiments of the invention relate to systems and methods for fabricating low density ceramic felt core materials which are sandwiched between two ceramic matrix composites (CMCs).
Sandwich structures are materials that consist of two thin load-bearing face plates joined to a thicker, but less-dense core material. Loads are carried by the face plates with the core acting as a load transfer medium. Depending on the application, the face plates may be fabricated from metal, plywood or fiber reinforced composites. The core may be fabricated from a hard foam or honeycomb material, or a rigid lightweight material.
Sandwich structures are commonly employed as building materials where a high strength to density is required, and are also often used in the aircraft industry. In addition to a high strength to density ratio, the sandwich structure should also possess a high load carrying capability and resistance to torsion. For a sandwich structure functioning as a structural material in a hot section of an aircraft engine, the material must also have good resistance to oxidation, together with high strength and toughness at elevated temperatures.
One problem with the fabrication of a sandwich type structure is forming a high-quality bond between the face plates and the core material. If the bond between the face plates is weak, the material will fail in shear and not support the full load from the face plates. In many structures, the face plates are joined to the core by use of adhesives. In sandwich structures employed for high-temperature applications, the use of adhesives to bond the face plates to the core material may lead to debonding of the face plates from the core due to different coefficients of thermal expansion among the materials. In addition, most high temperature glues shrink, outgas, and crack when heated to the application temperature. This ultimately results in a weak or failed bond.
Although there are various systems and methods of constructing ceramic matrix laminates, such systems and methods are not completely satisfactory. Therefore, improved systems and methods of constructing ceramic matrix laminates are desirable.